1. Field of the Invention
This invention relates generally to fluid distribution manifolds, and more specifically to thermoplastic distribution manifolds for use in a beverage dispensing device.
2. The Prior Art
A post-mix carbonated beverage dispensing system generates its own carbonated water from a pressurized supply of potable water, and then distributes the carbonated water to a post-mix valve or valves. Each post-mix valve mixes carbonated water with syrup and effects dispensing of a complete beverage. These dispensers are typically used by fast food retailers, theaters, convention centers, sports facilities and the like.
Most all post-mix dispensers have some type of manifold structure to distribute carbonated water from a single source, which may consist of a single carbonator connected to a plurality of dispensing valves. A typical dispenser will include four dispensing valves, and it is not uncommon to see up to twelve dispensing valves being supplied from a single carbonator. The structure that distributes the carbonated water plays an important role in beverage quality, as carbonated water is a very delicate substance in that it can become decarbonated very easily by temperature increases or agitation. Therefore, a manifold made of a material having a high heat capacity, or structural flaws in the interior water passages thereof, can cause unwanted warming of, or turbulence in, the water flow resulting in reduced carbonation and poor beverage quality. One known structure for distributing carbonated water consists of a molded plastic housing with metal ferrules for an inlet and plural outlets. However, such a device is generally located at a remote location from the cooling structure and, during stand by time, carbonated water in the housing can warm up and, as a result thereof, decarbonate. Leakage, ferrule breakage, stress cracks, and sanitation are also continually reoccurring problems with such manifolds.
A metal block with a bored out center section having bored and tapped transverse apertures using adapter fittings, has also been used. This equipment is expensive, heavy, bulky, leaky, very difficult to sanitize and generally is not an effective solution. A typical example is seen in U.S. Pat. No. 3,175,578.
The most recently commercially used structure for distributing carbonated water includes a manifold made of an elongate length of stainless steel tubing forming an elongate plenum. At least one end of the tube is closed and the other end may be an inlet or may be closed, and several transverse fittings are welded into apertures drilled transversely into the plenum tube. This structure has been in use for several years and is the least costly, and most structurally efficient device known for distributing carbonated water in a post-mix dispenser. A typical example of this structure is shown in U.S. Pat. No. 3,892,335. However, a major problem with this type of manifold concerns the welding of the transverse fittings to the plenum tube. Specifically, the problem can result from such welding wherein the weld causes an obstruction to be formed within the tube. Such obstructions can cause undesirable turbulence in the flow of the carbonated water. The existence of one or more of such defective outlets can not be easily determined, visually or otherwise, prior to actual use. Consequently, maintaining a high level of quality control in the manufacture of such manifolds can be very troublesome and costly. Sanitation problems are also a concern due to small, hard to clean crevices that can exist as a result of the welding process that can provide a location for bacterial growth. It has been proven to be a very time consuming and expensive task to establish, in the field, that a dispensing problem is due to a defective manifold. Thus, flawed manifolds present a substantial problem for the food and beverage industry.